Question Number 195628 by mr W last updated on 06/Aug/23 $$\underline{{an}\:{unsolved}\:{old}\:{question}\:#\mathrm{190875}} \\ $$$${a},\:{b},\:{c}\:{are}\:{real}\:{roots}\:{of}\:{the}\:{equation} \\ $$$${x}^{\mathrm{3}} −\mathrm{7}{x}^{\mathrm{2}} +\mathrm{4}{x}+\mathrm{1}=\mathrm{0}. \\ $$$${find}\:\frac{\mathrm{1}}{\:\sqrt[{\mathrm{3}}]{{a}}}+\frac{\mathrm{1}}{\:\sqrt[{\mathrm{3}}]{{b}}}+\frac{\mathrm{1}}{\:\sqrt[{\mathrm{3}}]{{c}}}=? \\ $$ Commented by Frix last…
Question Number 195653 by mustafazaheen last updated on 06/Aug/23 Answered by MM42 last updated on 06/Aug/23 $${e}−\mathrm{1}>\mathrm{1}\:\:\: \\ $$$$\Rightarrow{lim}_{{x}\rightarrow\:\mathrm{0}^{+} } \:\left({e}−\mathrm{1}\right)^{\frac{\sqrt{\mathrm{3}}}{{x}}} =\infty \\ $$$$\Rightarrow{lim}_{{x}\rightarrow\:\mathrm{0}^{−} }…
Question Number 195651 by York12 last updated on 06/Aug/23 $$\mathrm{0}<{x}<\mathrm{1} \\ $$$$\frac{\mathrm{1}}{\mathrm{1}+{x}^{\mathrm{1}} }+\frac{\mathrm{2}{x}}{\mathrm{1}+{x}^{\mathrm{2}} }+\frac{\mathrm{4}{x}^{\mathrm{3}} }{\mathrm{1}+{x}^{\mathrm{4}} }+\frac{\mathrm{8}{x}^{\mathrm{7}} }{\mathrm{1}+{x}^{\mathrm{8}} }+\frac{\mathrm{16}{x}^{\mathrm{15}} }{\mathrm{1}+{x}^{\mathrm{16}} }+….+\infty \\ $$$${evaluate}\:{the}\:{previous}\:{summation} \\ $$ Answered…
Question Number 195652 by mustafazaheen last updated on 06/Aug/23 $$ \\ $$$$\mathrm{e}^{\mathrm{x}+\mathrm{y}} −\mathrm{e}^{\mathrm{x}−\mathrm{y}} =\mathrm{1} \\ $$$$\mathrm{then}\:\mathrm{find}\:\:\:\frac{\mathrm{dy}}{\mathrm{dx}}=? \\ $$$$ \\ $$$$ \\ $$ Answered by MM42…
Question Number 195571 by York12 last updated on 05/Aug/23 $${let}\:{f}\left({x}+{y}\right)+{f}\left({x}−{y}\right)=\mathrm{2}{f}\left({x}\right){f}\left({y}\right)\wedge{f}\left(\frac{\mathrm{1}}{\mathrm{2}}\right)=−\mathrm{1} \\ $$$${compute}\:\underset{{k}=\mathrm{1}} {\overset{\mathrm{20}} {\sum}}\left[\frac{\mathrm{1}}{\mathrm{sin}\:\left({k}\right)\mathrm{sin}\:\left({k}+{f}\left({k}\right)\right)}\right] \\ $$ Answered by mahdipoor last updated on 05/Aug/23 $${x}=\mathrm{1}/\mathrm{2}\:\:\:{y}=\mathrm{0}\:\Rightarrow\:\mathrm{2}{f}\left(\mathrm{1}/\mathrm{2}\right)=\mathrm{2}{f}\left(\mathrm{1}/\mathrm{2}\right){f}\left(\mathrm{0}\right)\:\Rightarrow{f}\left(\mathrm{0}\right)=\mathrm{1} \\…
Question Number 195592 by mathlove last updated on 06/Aug/23 $${f}\left({x}\right)=\frac{\mathrm{1376}}{\left({x}−\mathrm{1}\right)^{{ln}\left(\frac{\mathrm{2}}{\mathrm{4689}}\right)} } \\ $$$${dom}\:{f}\left({x}\right)=? \\ $$$${answer}\:{this} \\ $$ Commented by bbbbbbbb last updated on 06/Aug/23 $$\boldsymbol{\mathrm{D}}\mathrm{omainf}\left(\mathrm{x}\right)=\mathrm{R}\backslash\left\{\mathrm{1}\right\}…
Question Number 195511 by Calculusboy last updated on 04/Aug/23 Answered by mr W last updated on 04/Aug/23 $${there}\:{are}\:{infinite}\:{values}\:{for}\:{k}+\mathrm{1}. \\ $$$$ \\ $$$${curve}\:{x}^{{y}} +{y}^{{x}} =\mathrm{8}\:{is}\:{symmetric}\:{about}\: \\…
Question Number 195454 by universe last updated on 02/Aug/23 Commented by mr W last updated on 03/Aug/23 $${see}\:{also}\:{Q}\mathrm{157749} \\ $$ Answered by Frix last updated…
Question Number 195419 by CrispyXYZ last updated on 02/Aug/23 $${x}\neq\mathrm{0}.\:\underset{{i}=\mathrm{1}} {\overset{{n}} {\sum}}{ix}^{{i}−\mathrm{1}} =? \\ $$ Answered by MathedUp last updated on 02/Aug/23 $${x}\neq\mathrm{0}.\:\underset{{i}=\mathrm{1}} {\overset{{n}} {\sum}}{ix}^{{i}−\mathrm{1}}…
Question Number 195413 by Calculusboy last updated on 02/Aug/23 Commented by Rasheed.Sindhi last updated on 02/Aug/23 $${x}^{{y}} +{y}^{{x}} =\mathrm{8}\Rightarrow{x}={y}=\mathrm{2} \\ $$$${x}+{y}={k}^{\mathrm{2}} \Rightarrow{k}^{\mathrm{2}} =\mathrm{2}+\mathrm{2}=\mathrm{4}\Rightarrow{k}=\pm\mathrm{2} \\ $$$${k}+\mathrm{1}=\pm\mathrm{2}+\mathrm{1}=\mathrm{3},−\mathrm{1}…